Process for producing an omega-functionalized aliphatic carboxylic acid and intermediate products of said process

ABSTRACT

A process for producing an omega-functionalized aliphatic carboxylic acid starting from cyclohexanone and omega-functionalized α-olefins. The process comprises an addition step, an oxidation step, an isomerization step, one or more hydrogenation steps and hydrolysis. The process allows to use raw materials that are available at low cost and to achieve high selectivity and high yield with industrially simple steps. The process includes the production of new intermediate products.

This application is a 371 of PCT/EP94/01865 filed Jun. 8, 1994.

The present invention relates to a process for producing anomega-functionalized aliphatic carboxylic acid that has over 7 carbonatoms and to the intermediate products of this process.

More particularly, the present invention relates to the production ofaliphatic carboxylic acids that have more than 7 carbon atoms and can beused in the production of polyamides with a large number of carbonatoms, even more particularly polyamides with 9 carbon atoms (nylon 9and nylon 6,9). These polyamides are particularly appreciated due totheir mechanical and elastic characteristics. Despite this, currentworldwide industrial production of polyamide 9 is practicallynonexistent due to lack of an industrially feasible process forproducing 9 amino nonanoic acid with the required degree of purity.

The present invention furthermore relates particularly to the productionof 1,9-nonandioic acid (azelaic acid), which is used in the field oflubricants, polyester and alkyd resins, as plasticizer and as a drug fordermatological use, and in the production of polyamide 6,9.

A process for oxidizing ketones, including cyclic ketones, by usingpermonosulfuric acid as an oxidizing agent has been known since the lastcentury as the Baeyer-Villiger reaction (A. Von Baeyer and V. Villiger,Ber. 1899, 32, 3265; 1400, 33, 858). Other oxidizing agents have beenused for this reaction, such as for example: peracetic acid, describedby R. Criegel (Liebig Annalen, 1948, 560, 127) and in UK patent No.1,203,752, peracid salts such as magnesium permonophthalate described inSyntesis 1015-1017, 1987, or persalts such as sodium perborate,described in U.S. Pat. No. 4,988,825, whereas the agent used most ism-chloroperbenzoic acid. More recently, methods have been described forsynthesizing lactones from ketones, using molecular oxygen in thepresence of catalysts, Tetrahedron Lett. 33,75557-60, 1992. In general,the synthesis of lactones starting from cyclic ketones has unpredictableregioselectivity and chemoselectivity.

Processes for producing polyamides 9 are known and are described by K.A. Pollart and R. E. Miller, (J. Am. Chem. Soc., 27, 2392, 1962), byWilliam R. Miller et al. (Ind. Eng. Chem. Prod. Res. Develop., Vol 10,No. 4, 1971) and by R. B. Perkins, Jr. et al. (Journal of the AmericanOil Chemists' Society, Vol 52, November 1975); processes for producingazelaic acid are also known and described in Ullmann's Encyclopedia ofIndustrial Chemistry, fifth edition, volume A 8, pages 523-539, and inthe Kirk-Othmer Enc., Vol. 7, page 623. These known processes are allbased on a complex process for the ozonolysis of fatty acids of naturalorigin such as oleic acid or soya oil. The ozonolysis step is delicateand intrinsically dangerous and produces, at the end of the process, amixture of unsaturated products that are very difficult to purify andfor which purification is in any case industrially possible only up to80-90%. Furthermore, the availability and characteristics of the initialstarting products fluctuate. Finally, it is unavoidable to also obtainadditional co-products. For example, starting from oleic acid oneobtains azelaic acid but also, unavoidably, pelargonic acid, with severelimitations to the free use of the individual products.

A process for synthesizing 9 amino nonanoic acid, starting from sabacicacid by means of a monoesterification, ammonolysis and Hofmanndegradation has been described (W. Baoren et al, Polymer Communications,(1), 27-32, 1984. However this process has a very low selectivity andafter 10 years no industrial application is known.

U.S. Pat. No. 4,322,547 describes a process which is based on thecatalytic iron-copper system to obtain 9 amino nonanoic acid and azelaicacid starting from cyclohexanone and acrylonitrile. This process entailsthe use of amounts of catalyst, by weight, that are extremely high andindeed comparable with the weight of the product obtained. Furthermore,the copper must be introduced in the process before the iron, andtherefore after mixing it is very difficult to separate the iron fromthe copper to recycle them; problems accordingly arise in disposing ofthe used and mixed catalyst. The by-products that are obtained arefurthermore very difficult to separate.

Due to the above indicated reasons, after 15 years this process has hadno industrial application, whereas the above described ozonolysisprocess is still industrially in use after more than 20 years.

The aim of the present invention is therefore to solve the problems anddrawbacks of known processes, allowing to obtain highly pure productsthat have high selectivity so as to attain the "polymer-grade" purityrequired to produce polyamides 9 or 6,9 and "pharmaceutical-productgrade" purity for azelaic acid.

An object is to start from industrial products of petrochemical originthat have a low cost and are widely available.

Another object is to allow to obtain a single desired final productwithout accessory co-productions.

This aim, these objects and others are achieved by the process accordingto the invention for producing an omega-functionalized aliphatic-chaincarboxylic acid with more than 7 carbon atoms, which includes thefollowing steps:

(i) the addition, in a basic environment, of the compound with formula(1) ##STR1## and of the compound with formula (2)

    CH.sub.2 ═CR.sup.5                                     ( 2)

where each one of R¹, R², R³, and R⁴ is: hydrogen, alkyl, alkyl aryl,halogen, or hydroxyl; R⁵ is Y or a group that can be transformed into Ywith known methods: Y is --COOH, --CN, --CONH₂, or COOR⁶ ; and R⁶ is anoptionally substituted alkyl or aryl radical, obtaining the compoundwith formula (3) ##STR2## where R¹ -R⁵ have the above specified meaning;

(ii) the oxidation of the compound with formula (3), obtaining thecompound with formula (5)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --R.sup.7 --(CH.sub.2).sub.n --R.sup.5                              ( 5)

where R¹ -R⁵ have the above specified meaning; R7 is CH═CH or CHR⁸ --CH₂; R⁸ is OH, OCOCH₃, OCH₃, OEt, or halogen; m is 0, 1 or 2; n is 0 or 1;and m+n is 1 or 2;

(iii) the hydrogenation or hydrogenolysis of the compound with formula(5), obtaining an omega-functionalized aliphatic-chain carboxylic acid.

A first embodiment of the process is illustrated by way ofnon-limitative example in the following reaction diagram (I): ##STR3##

A second embodiment of the process is illustrated by way ofnon-limitative example in the following reaction diagram (II): ##STR4##

Other embodiments of the process are shown by way of non-limitativeexample in the following reaction diagram (III): ##STR5##

Preferably, step (i) is performed in a basic environment, morepreferably in the presence of a compound chosen among ammonia, primary,secondary aliphatic and alicyclic amines, and their mixture withtertiary aliphatic and alicyclic amines. The temperature of the reactionin step (i) is preferably between 20° and 200° C., more preferablybetween 40° and 180° C., and more preferably between 60° and 160° C.

The compound with formula (3) can be constituted for example by:3-(2-cyclohexanonyl)propionitrile, 3-(2-cyclohexanonyl)propionic acid,methyl 3-(2-cyclohexanonyl)propionate, butyl3-(2-cyclohexanonyl)propionate.

According to a first embodiment, the oxidation step (ii) can beperformed in the presence of an oxidizing agent chosen among hydrogenperoxide, an organic peracid and oxygen. Preferably, the organic peracidis a cycloaliphatic peracid and particularly a cyclohexane percarboxylicacid, optionally substituted in its cycloaliphatic ring. This peracidhas the specific advantage that it can be obtained starting fromcyclohexancarboxylic acid, which is a widely available, highly pure andlow-cost product.

The oxidation step (ii) can be performed in the presence of an organicacid with less than 5 carbon atoms, preferably in the presence of acatalyst which is constituted by a strong acid, preferably methanesulfonic acid.

According to a second embodiment, the oxidation step (ii) comprises ahydrolysis step conducted in an aqueous phase in the presence of anagent chosen among NaOH, alcohol, and acetic acid. This secondembodiment is particularly suitable when Y is --COOH. In this case, R⁷is preferably CHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃ --CH₂, CHOEt--CH₂,CHhalogen--CH₂.

As an alternative, according to another embodiment, step (ii) isperformed with molecular oxygen in the presence of a catalyst, forexample a Ni catalyst complexed with 1,3-diketone or an iron oxide andan aldehyde.

The subsequent step (iii) can furthermore include dehydration ordehydrohalogenation or dealkoxylation of the compound with formula (5)to obtain the compound with formula (6)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --CH═CH--(CH.sub.2).sub.n --COOH                      (6)

where R¹ -R⁴, R⁷, m and n have the same meaning, and hydrogenation ofthe compound with formula (6) may also be included. This hydrogenationcan be performed at a pressure between 1 and 10 bar (0.1 and 1 MPa),preferably between 2 and 5 bar (0.2 and 0.5 MPa).

If Y is --CN and R⁷ is CH═CH, the hydrogenation step (iii) isadvantageously performed at a temperature between 20° and 200° C.,preferably at a temperature between 30° and 130° C., more preferably ata temperature between 40° and 70° C., and at a pressure between 1 and200 bar (0.1 and 20 MPa), preferably at a pressure between 2 and 130 bar(0.2 to 13 MPa) to obtain an amino acid.

If R⁷ is CH═CH, the hydrogenation step (iii) is advantageously performedat a temperature between 20° and 200° C., preferably at a temperaturebetween 30° and 130° C., more preferably at a temperature between 40°and 70° C., and at a pressure between 1 and 200 bar (0.1 and 20 MPa),preferably at a pressure between 2 and 130 bar (0.2 and 13 MPa) andcomprises basic saponification and acidification to obtain adicarboxylic acid.

If Y is --CN and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃ --CH₂,CHOEt--CH₂, CHhalogen--CH₂, the hydrogenation step (iii) isadvantageously performed at a temperature between 20° and 200° C.,preferably at a temperature between 30° and 130° C., more preferably ata temperature between 40° and 70° C., and at a pressure between 1 and200 bar (0.1 and 20 MPa), preferably at a pressure between 2 and 130 bar(0.2 and 13 MPa) to obtain an amino acid.

If Y is --COOH or COOR⁶, where R⁶ has the same meaning, and R⁷ isCHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃ --CH₂, CHOEt--CH₂, CHhalogen--CH₂, thehydrogenation step (iii) is advantageously performed at a temperaturebetween 20° and 200° C., preferably at a temperature between 30° and130° C., more preferably at a temperature between 40° and 70° C., and ata pressure between 1 and 200 bar (0.1 and 20 MPa), preferably at apressure between 2 and 130 bar (0.2 and 13 MPa), and comprises basicsaponification and acidification to obtain a dicarboxylic acid.

If R⁷ is CHOH--CH₂, step (iii) can include dehydration ordehydrohalogenation or dealkoxylation of the compound with formula (5).

The invention furthermore relates to the following intermediate productsthat can be isolated from the reaction environment.

The compound with formula (5)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --R.sup.7 --(CH.sub.2).sub.n --R.sup.5                              ( 5)

where each one of R¹, R², R³, and R⁴ is: hydrogen, alkyl, alkyl aryl,halogen or hydroxyl; R⁵ is Y or a group that can be transformed into Ywith known methods; Y is --COOH, --CN, --CONH₂, or COOR⁶ ; R⁶ is anoptionally substituted alkyl or aryl radical; R⁷ is CH═CH or CHR⁸ --CH₂; R⁸ is OH, OCOCH₃, OCH₃, OEt, or halogen; m is 0, 1 or 2; n is 0 or 1;and m+n is 1 or 2. According to a preferred embodiment, the compoundwith formula (5) has the formula (8)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --CH═CH--CH.sub.2 --R.sup.5                           ( 8)

where R¹ -R⁷ have the same meaning and m is 0 or 1. According to an evenmore preferred embodiment, the compound with formula (5) has the formula(7)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --CH═CH--R.sup.5                                      ( 7)

where R¹ -R⁷ have the same meaning and m is 1 or 2. The compounds withformulas (10) and (11) are particularly preferred:

    HOOC--(CH.sub.2).sub.5 --CH═CH--COOH                   (10)

    HOOC--(CH.sub.2).sub.5 --CH═CH--CN                     (11)

According to another embodiment, the compound with formula (5) has theformula (9):

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --R.sup.7 --CH.sub.2 --R.sup.5                                      ( 9)

where R¹ -R⁵ have the same meaning; R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂,CHOCH₃ --CH₂, CHOET--CH₂, CHhalogen--CH₂ ; and m is 1 or 2. Preferably,the compound with formula (5) has the formula (12):

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --CHOH--(CH.sub.2).sub.2 --R.sup.5                        ( 12)

where R¹ --R⁵ and m have the same meaning.

The invention also relates to the compound with formula (13)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.z --CN (13)

where each one of R¹, R², R³, R⁴ is: hydrogen, alkyl, alkyl aryl,halogen, or hydroxyl; and z is 3 or 4.

The following compounds with formulas (14) and (16) are preferredembodiments:

    HOOC--(CH.sub.2).sub.5 --CH═CH--CN                     (14)

    HOOC--(CH.sub.2).sub.7 --CN                                (16)

The following examples are enclosed by way of non-limitative example ofthe present invention.

EXAMPLE 1

7-cyanoethyl-2-oxepanone

A reactor is loaded with 500 g of 3-(2-cyclohexanonyl)propionitrile in1000 ml of n-hexane; the reaction mixture is heated to 50° C. and asolution of 520 g of perhexahydrobenzoic acid in 3000 ml of n-hexane isadded. The reaction mixture is kept agitated for three hours at 55° C.and then the lower phase, mainly formed by 7-cyano-ethyl-2-oxepanone andhexahydrobenzoic acid, is separated, while the upper phase containshexahydrobenzoic acid and small amounts of unreacted cyanoketone.Treatment of the lower phase with n-hexane allows to isolate 515 g of7-cyanoethyl-2-oxepanone, equal to a yield of over 93%, with 99% ketoneconversion. The 7-cyanoethyl-2-oxepanone (m.p. 35° C.) is identified bymeans of I.R. (KBr) analysis techniques: 2970, 2870, 2245, 1720, 1175cm⁻¹ and mass spectrometry by electron-impact ionization (70 eV): 168,150, 139, 122, 113, 95, 84, 67, 55, 41. Analytically calculated valuesfor C₉ H₁₁ NO₂ (167.21): C 64.65%, H 7.83%, N 8.38%. Found: C 64.51%, H7.98%, N 8.46%.

EXAMPLE 2

7-cyanoethyl-2-oxepanone

A reactor is loaded with 151 g of 3-(2-cyclohexanonyl)propionitrile in500 ml of n-hexane and 260 g of m-chloroperbenzoic acid (70% titer)dissolved at 50° C. in 2000 ml of n-hexane in 30 minutes. The solutionis heated to 55° C. for 15 hours. Cooling of the solution separates, incrystalline form, part of the m-chlorobenzoic acid which is scarcelysoluble in the system, together with a heavy liquid phase which isformed by 7-cyanoethyl-2-oxepanone and by m-chlorobenzoic acid. 71.5 gof 7-cyanoethyl-2-oxepanone, impure with m-chlorobenzoic acid, arerecovered from the lower phase. 24 g of 7-cyanoethyl-2-oxepanone arerecovered from the upper phase by concentration and severalcrystallizations. Conversion over the initial ketone is 85%. Yield onthe converted amount is 57%.

EXAMPLE 3

7-cyanoethyl-2-oxepanone

A reactor is loaded with 151 g of 3-(2-cyclohexanonyl)propionitrile in500 ml of glacial acetic acid. This solution receives the addition of210 g of 40% peracetic acid in 2 hours, keeping the temperature between30° and 40° C. After the addition has been completed, the reactionmixture is heated to 60° C. for 3 hours to complete the reaction. Thereaction mixture is distilled in vacuum, recovering acetic acid andobtaining 150 g of an oily residue that contains 35%7-cyanoethyl-2-oxepanone together with 65% by-products, with 98%conversion of the initial ketone (GLC analysis).

EXAMPLE 4

8-cyanoocten-7-oic acid

167 g of 7-cyanoethyl-2-oxepanone are heated in a reactor to atemperature of 450° C. in inert atmosphere, collecting 0.5 g/minute ofliquid condensed product mainly formed by 8-cyano-7-octanoic acid, with95% lactone conversion and 93% selectivity.

The product, with a b.p. of 155° C. at 0.05 torr, was identified withI.R. (film) analysis techniques: 3500, 3050, 3000, 2940, 2870, 2260,1710, 1610, 1420, 975 cm⁻¹ and mass spectrometry by electron-impactionization (70 eV): 168, 149, 121, 94, 80, 67, 55, 53, 41, 39.Analytically calculated values for C₉ H₁₃ NO₂ (167.21): C 64.65%, H7.83%, N 8.30%. Found: C 64.55%, H 8.01%, N 8.45%.

EXAMPLE 5

8-cyanooctanoic acid

167 g of 8-cyano-7-octanoic acid dissolved in 800 ml of toluene arehydrogenated selectively at 2 bar in an autoclave in the presence of 10g of Pd on charcoal at 5% at 50° C. for 5 hours.

After filtration of the catalyst and evaporation of the solvent, 165 gof an oil that distills at 150° C. at 0.05 torr are recovered. Theproduct has been identified as 8-cyanooctanoic acid by I.R. (film)analysis techniques: 3400, 3000, 2950, 2875, 2260, 1710, 1430 cm⁻¹ andmass spectrometry by electron-impact ionization (70 eV): 170, 152, 140,123, 110, 94, 83, 69, 55, 41. Analytically calculated values for C₉ H₁₅NO₂ (169.22): C 63.88%, H 8.93%, N 8.28%. Found: C 63.76%, H 9.12%, N8.37%.

EXAMPLE 6

azelaic acid

83.5 g of 8-cyanooctanoic acid dissolved in 300 ml of dimethyl etherethylene glycol are heated to 130° C. for 4 hours in the presence of 50gof 40% caustic soda. After cooling, the reaction mixture is diluted withwater, then acidified to pH 5 with diluted sulfuric acid, and then theprecipitated solid is filtered. After drying, 92 g of azelaic acid witha m.p. of 107° C. are obtained.

EXAMPLE 7

9-aminononanoic acid

167 g of 8-cyano-7-octanoic acid dissolved in 1000 ml of propyl alcoholare hydrogenated at 50° C. and 80 bar for 4 hours, using 20 g ofNi-Raney as a catalyst. The catalyst is filtered out and the solution isconcentrated. Cooling and purification produce 9-aminononanoic acid inthe form of a crystalline solid product with a m.p. of 190°-193° C.

We claim:
 1. Process for producing an omega-functionalizedaliphatic-chain carboxylic acid with more than 7 carbon atoms,comprising the following steps:(i) the addition, in a basic environment,of the compound with formula (1) ##STR6## and of the compound withformula (2)

    CH.sub.2 ═CR.sup.5                                     ( 2)

where each one of R¹, R², R³, and R⁴ is: hydrogen, alkyl, alkyl aryl,halogen, or hydroxyl; R⁵ is Y or a group that can be transformed into Ywith known methods: Y is --COOH, --CN, --CONH₂, or COOR⁶ ; and R⁶ is anoptionally substituted alkyl or aryl radical, obtaining the compoundwith formula (3) ##STR7## where R¹ -R⁵ have the above specified meaning;(ii) the oxidation of the compound with formula (3), obtaining thecompound with formula (5)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --R.sup.7 --(CH.sub.2).sub.n --R.sup.5                              ( 5)

where R¹ -R⁵ have the above specified meaning; R⁷ is CH═CH or CHR⁸ --CH₂; R⁸ is OH, OCOCH₃, OCH₃, OEt, or halogen; m is 0, 1 or 2; n is 0 or 1;and m+n is 1 or 2; said oxidation being performed in the presence of anorganic acid with less than five carbon atoms, preferably in thepresence of a catalyst which is constituted by a strong acid; (iii) thehydrogenation or hydrogenolysis of the compound with formula (5),obtaining an omega-functionalized aliphatic-chain carboxylic acid. 2.Process according to claim 1, wherein said step (i) is performed in abasic environment, in the presence of a compound chosen among ammoniaand primary, secondary or tertiary aliphatic and alicyclic amines. 3.Process according to claim 1, wherein step (i) is performed at atemperature between 20° and 160° C.
 4. Process according to claim 1,wherein said oxidation step (ii) is performed in the presence of anoxidizing agent chosen between hydrogen peroxide and an organic peracid.5. Process according to claim 1, wherein said oxidation step (ii) isperformed in the presence of a catalyst which is constituted by methanesulfonic acid.
 6. Process according to claim 1, wherein Y is --COOH andsaid oxidation step (ii) comprises a hydrolysis step performed in anaqueous phase in the presence of an agent chosen among NAOH, alcohol,and acetic acid.
 7. Process according to claim 6, wherein R⁷ isCHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃ --CH₂, CHOEt--CH₂, CHhalogen--CH₂, andsaid step (iii) comprises dehydration or dehydrohalogenation ordealkoxylation of the compound with formula (5) to obtain the compoundwith formula (6)

    R.sup.1 OOC--CHR.sup.2 --CHR.sup.3 --CHR.sup.4 --(CH.sub.2).sub.m --CH═CH≧(CH.sub.2).sub.n --COOH                (6)

where R¹ -R⁴, R⁷, m and n have the same meaning, and compriseshydrogenation of the compound with formula (6).
 8. Process according toclaim 7, wherein said hydrogenation is performed at a pressure between 1and 10 bar (0.1 and 1 MPa).
 9. Process according to claim 1, where Y is--CN and R⁷ is CH═CH, said hydrogenation step (iii) is performed at atemperature between 20° and 200° C. and at a pressure between 1 and 200bar (0.1 and 20 MPa) to obtain an amino acid.
 10. Process according toclaim 1, wherein R⁷ is CH═CH, said hydrogenation step (iii) is performedat a temperature between 20° and 200° C. and at a pressure between 1 and200 bar (0.1 and 20 MPa) and comprises basic saponification andacidification to obtain a dicarboxylic acid.
 11. Process according toclaim 1, wherein Y is --CN and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃--CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step (iii) isperformed at a temperature between 20° and 200° C. and at a pressurebetween 1 and 200 bar (0.1 and 20 MPa) to obtain and amino acid. 12.Process according to claim 1 wherein Y is --COOH or COOR⁶, where R⁶ hasthe same meaning as in claim 1, and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂,CHOCH₃ --CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step(iii) is performed at a temperature between 20° and 200° C. and at apressure between 1 and 200 bar (0.1 and 20 MPa) and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 13.Process according to claim 1, wherein R⁷ is CHOH--CH₂, said step (iii)comprising dehydration or dehydrohalogenation or dealkoxylation of thecompound with formula (5).
 14. Process according to claim 1, whereinstep (i) is performed at a temperature between 40° and 140° C. 15.Process according to claim 1, wherein step (i) is performed at atemperature between 60° and 100° C.
 16. Process according to claim 7,wherein said hydrogenation is performed at a pressure between 2 and 5bar (0.2 and 0.5 MPa).
 17. Process according to claim 1, where Y is --CNand R⁷ is CH═CH, said hydrogenation step (iii) is performed at atemperature between 30° and 130° C. and at a pressure between 1 and 200bar (0.1 and 20 MPa) to obtain an amino acid.
 18. Process according toclaim 1, where Y is --CN and R⁷ is CH═CH, said hydrogenation step (iii)is performed at a temperature between 40° and 70° C. and at a pressurebetween 2 and 130 bar (0.2 and 13 MPa) to obtain an amino acid. 19.Process according to claim 1, wherein R⁷ is CH═CH, said hydrogenationstep (iii) is performed at a temperature between 30° and 130° C. and ata pressure between 1 and 200 bar (0.1 and 20 MPa) and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 20.Process according to claim 1, wherein R⁷ is CH═CH, said hydrogenationstep (iii) is performed at a temperature between 30° and 130° C. and ata pressure between 2 and 130 bar (0.2 and 13 MPa), and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 21.Process according to claim 1, wherein R⁷ is CH═CH, said hydrogenationstep (iii) is performed at a temperature between 40° and 70° C. and at apressure between 2 and 130 bar (0.2 and 13 MPa), and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 22.Process according to claim 1, wherein Y is --CN and R⁷ is CHOH--CH₂,CHOCOCH₃ --CH₂, CHOCH₃ --CH₂, CHOEt--CH₂ or CHhalogen--CH₂, saidhydrogenation step (iii) is performed at a temperature between 20° and200° C. and at a pressure between 2 and 130 bar (0.2 and 13 MPa) toobtain and amino acid.
 23. Process according to claim 1, wherein Y is--CN and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃ --CH₂, CHOEt--CH₂ orCHhalogen--CH₂, said hydrogenation step (iii) is performed at atemperature between 30° and 130° C., and at a pressure between 1 and 200bar (0.1 and 20 MPa) to obtain and amino acid.
 24. Process according toclaim 1, wherein Y is --CN and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂, CHOCH₃--CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step (iii) isperformed at a temperature between 40° and 70° C. and at a pressurebetween 1 and 200 bar (0.1 and 20 MPa) to obtain and amino acid. 25.Process according to claim 1 wherein Y is --COOH or COOR⁶, where R⁶ hasthe same meaning as in claim 1, and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂,CHOCH₃ --CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step(iii) is performed at a temperature between 20° and 200° C. and at apressure between 2 and 130 bar (0.2 and 13 MPa) and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 26.Process according to claim 1 wherein Y is --COOH or COOR⁶, where R⁶ hasthe same meaning as in claim 1, and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂,CHOCH₃ --CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step(iii) is performed at a temperature between 30° and 130° C. and at apressure between 1 and 200 bar (0.1 and 20 MPa) and comprises basicsaponification and acidification to obtain a dicarboxylic acid. 27.Process according to claim 1 wherein Y is --COOH or COOR⁶, where R⁶ hasthe same meaning as in claim 1, and R⁷ is CHOH--CH₂, CHOCOCH₃ --CH₂,CHOCH₃ --CH₂, CHOEt--CH₂ or CHhalogen--CH₂, said hydrogenation step(iii) is performed at a temperature between 40° and 70° C. and at apressure between 2 and 130 bar (0.2 and 13 MPa) and comprise s basicsaponification and acidification to obtain a dicarboxylic acid.